For the recognition of three-dimensional (3-D) shape and measurement of 3-D position of objects, it is important that a vision system be able to measure the 3-D data on dense points in the scene. One approach is to measure the distance on the basis of the triangulation principle from the disparity of two images. This stereo method encounters difficulties in finding correspondence of features between two images. This correspondence problem can be solved geometrically by adding one more camera, that is, by trinocular vision. The principles and implementation details of this trinocular vision approach are outlined.